Fed edges in front for the first time in the breaker with a big serve (3-4) before the Greek curls a forehand winner into the corner to restore parity (4-4).
Where many of his contemporaries spend their free time playing computer games like Fortnite and Fifa, Tsitsipas - only 20 years old and the 15th best tennis player in the world - is happier discussing his passion for photography, podcasting and solo travel.
Berdych has been a player reborn in Australia after taking the second half of last season off with a back injury but he was overwhelmed in the early stages and did not get on the board until the 10th game.
7:28AM If Tsitsipas needs any more motivation ahead of his daunting clash with Federer he could turn to American Frances Tiafoe and the progress he has made these championships.
He enjoyed a breakthrough 2018 and has built on that superbly in Australia, showing his talent and belief in a 7-5, 7-6, 6-7, 7-5 victory that featured no end of tight moments.
Despite the gulf in experience, seven-time slam winner Mats Wilander, speaking on Eurosport, believes Tsitsipas has the game and personality to cause a huge shock.
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- 'Tsitsipas is like Nadal: he won't be fazed by facing Federer' - WilanderTennis World
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